server/common/noise.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2010 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * 
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

#include "noise.h"

/////////////////////////////////////////////////////////////////////////////

noise2d::noise2d (uint32_t seed)
{
  seedable_rand_gen rng (seed);

  for (int i = 0; i < 256; ++i)
    {
      vec2d rv;
      rv[0] = rng () - 0.5f;
      rv[1] = rng () - 0.5f;

      // normalise
      float mag = 1.f / sqrtf (rv[0] * rv[0] + rv[1] * rv[1]);

      rv[0] *= mag;
      rv[1] *= mag;

      rvec[i][0] = rv[0];
      rvec[i][1] = rv[1];
    }

  rvmap[0].seed (rng);
  rvmap[1].seed (rng);
}

float
noise2d::noise (float x, float y)
{
  int ix = floorf (x); float fx = x - ix;
  int iy = floorf (y); float fy = y - iy;

  float v = 0;

  for (int j = -1; j <= 2; ++j)
    for (int i = -1; i <= 2; ++i)
      {
        float Ax = fx - i;
        float Ay = fy - j;

        float d = Ax * Ax + Ay * Ay;

        if (d < 4)
          {
            float t1 = 1 - d / 4;
            float t2 = t1 * t1;
            float t4 = t2 * t2;

            float p = (4 * t1 - 3) * t4;

            int h = rvmap[0](ix + i) ^ rvmap[1](iy + j);
            float G0 = rvec[h & 0xff][0];
            float G1 = rvec[h & 0xff][1];
            //vec2d G = rvec[h & 0xff];

            v += (Ax * G0 + Ay * G1) * p;
          }
      }

  return clamp (v * 2, -.9999999f, .9999999f);
}

#if 0||ABSTRACTION_PENALTY_IS_GONE
float
noise2d::noise (float x, float y)
{
  vec2d X = vec2d (x, y);
  gen_vec<2,int> I = floor (X);
  vec2d F = X - I;

  float v = 0;

  for (int j = -1; j <= 2; ++j)
    for (int i = -1; i <= 2; ++i)
      {
        vec2d A = F - vec2d (i, j);

        float d = A * A;
  
        if (d < 4)
          {
            int h = rvmap [0](I[0] + i) ^ rvmap [1](I[1] + j);
            float *G = rvec [h & 0xff];
  
            float t1 = 1 - d / 4;
            float t2 = t1 * t1;
            float t4 = t2 * t2;

            float p = (4 * t1 - 3) * t4;
            v += A * vec2d (G[0], G[1]) * p;
          }
      }
    
  return clamp (v * 2, -.9999999f, .9999999f);
} 
#endif

/////////////////////////////////////////////////////////////////////////////

noise3d::noise3d (uint32_t seed)
{
  seedable_rand_gen rng (seed);

  for (int i = 0; i < 256; ++i)
    {
      for (int j = 0; j < 3; ++j)
        rvec [i][j] = rng () - 0.5f;

      // normalise
      float mag = 1.f / sqrtf (rvec [i][0] * rvec [i][0]
                             + rvec [i][1] * rvec [i][1]
                             + rvec [i][2] * rvec [i][2]);

      rvec [i][0] *= mag;
      rvec [i][1] *= mag;
      rvec [i][2] *= mag;
    }

  rvmap [0].seed (rng);
  rvmap [1].seed (rng);
  rvmap [2].seed (rng);
}

float
noise3d::noise (float x, float y, float z)
{
  int ix = floorf (x); float fx = x - ix;
  int iy = floorf (y); float fy = y - iy;
  int iz = floorf (z); float fz = z - iz;

  float v = 0;

  for (int j = -1; j <= 2; ++j)
    for (int i = -1; i <= 2; ++i)
      for (int k = -1; k <= 2; ++k)
        {
          float Ax = fx - i;
          float Ay = fy - j;
          float Az = fz - k;

          float d = Ax * Ax + Ay * Ay + Az * Az;

          if (d < 4)
            {
              int h = rvmap [0](ix + i) ^ rvmap [1](iy + j) ^ rvmap [2](iz + k);
              float *G = rvec [h & 0xff];

              float t1 = 1 - d / 4;
              float t2 = t1 * t1;
              float t4 = t2 * t2;

              // (4t⁵ - 3t⁴)
              float p = (4 * t1 - 3) * t4;
              v += (Ax * G[0] + Ay * G[1] + Az * G[2]) * p;
            }
        }

  return clamp (v * 2, -.9999999f, .9999999f);
}

float
noise3d::noise (float x, float y, float z, float nx, float ny, float nz)
{
  int ix = floorf (x); float fx = x - ix;
  int iy = floorf (y); float fy = y - iy;
  int iz = floorf (z); float fz = z - iz;

  float v = 0;

  for (int j = -1; j <= 2; ++j)
    for (int i = -1; i <= 2; ++i)
      for (int k = -1; k <= 2; ++k)
        {
          float Dx = fx - i;
          float Dy = fy - j;
          float Dz = fz - k;

          float e = Dx * nx + Dy * ny + Dz * nz;

          float o = 1 - abs (e);

          if (o > 0)
            {
              float Ax = Dx - e * nx;
              float Ay = Dy - e * ny;
              float Az = Dz - e * nz;

              float d = Ax * Ax + Ay * Ay + Az * Az;

              if (d < 4)
                {
                  int h = rvmap [0](ix + i) ^ rvmap [1](iy + j) ^ rvmap [2](iz + k);
                  float *G = rvec [h & 0xff];

                  float t1 = 1 - d / 4;
                  float t2 = t1 * t1;
                  float t4 = t2 * t2;

                  float o2 = o * o;

                  // (4t⁵ - 3t⁴) * (3o³ - 2o²)
                  float p = (4 * t1 - 3) * t4 * (3 * o2 - 2 * o2 * o);
                  v += (Ax * G[0] + Ay * G[1] + Az * G[2]) * p;
                }
            }
        }

  return clamp (v * 2, -.9999999f, .9999999f);
}

frac_gen::frac_gen (float hurst_expo, float lacunarity)
: h (hurst_expo), lac (lacunarity), noise2d (0)
{
  float exsum = 0;

  for (int i = 0; i < MAX_OCTAVES; ++i)
    {
      ex [i] = powf (lac, -h * i);
      exsum += ex [i];
      fbm_mul [i] = 0.5f / (exsum * 0.75f); // .75f is a heuristic
      rot [i].set (0.4488f * i);
    }
}

float
frac_gen::fBm (float x, float y, int octaves)
{
  float v = 0.f;

  for (int i = 0; i < octaves; ++i)
    {
      rot [i](x, y);
      
      v += noise (x + i, y) * ex [i];

      x *= lac;
      y *= lac;
    }

  return clamp (v * fbm_mul [octaves - 1] + 0.5f, 0.f, .9999999f);
}

float
frac_gen::turbulence (float x, float y, int octaves)
{
  float v = 0.f;

  for (int i = 0; i < octaves; ++i)
    {
      rot [i](x, y);

      v += fabsf (noise (x + i, y)) * ex [i];

      x *= lac;
      y *= lac;
    }

  return clamp (v * fbm_mul [octaves - 1] * 2.f, 0.f, .9999999f);
}

float
frac_gen::multifractal (float x, float y, int octaves, float offset)
{
  float v = 1.f;

  for (int i = 0; i < octaves; ++i)
    {
      rot [i](x, y);

      v *= noise (x, y) * ex [i] + offset;

      x *= lac;
      y *= lac;
    }

  return clamp (v * 0.5f, 0.f, .9999999f);
}

float
frac_gen::heterofractal (float x, float y, int octaves, float offset)
{
  float v = noise (x, y) + offset;
  int i;

  for (i = 1; i < octaves; ++i)
    {
      rot [i](x, y);

      x *= lac;
      y *= lac;

      v += v * (noise (x, y) * ex [i] + offset);
    }

  return v / powf (2., octaves);
}

float
frac_gen::hybridfractal (float x, float y, int octaves, float offset, float gain)
{
  float v = (noise (x, y) + offset) * ex [0];
  float weight = v;
  int i;

  for (i = 1; i < octaves; ++i)
    {
      rot [i](x, y);

      x *= lac;
      y *= lac;

      min_it (weight, 1.f);

      float sig = (noise (x, y) + offset) * ex [i];
      v += weight * sig;
      weight *= gain * sig;
    }

  return clamp (v * 0.5f + 0.5f, 0.f, .9999999f);
}

// http://www.gamasutra.com/view/feature/3098/a_realtime_procedural_universe_.php?page=2
float
frac_gen::terrain (float x, float y, int octaves)
{
  float v = 0.f;

  for (int i = 0; i < octaves; ++i)
    {
      rot[i] (x, y);

      v += noise (x + i, y) * ex [i];

      x *= lac;
      y *= lac;
    }

  v *= fbm_mul [octaves - 1];

  return v <= 0.f ? - powf (-v, 0.7f) : powf (v, 1. + noise (x, y) * v);
}

float
frac_gen::terrain2 (float x, float y, int octaves)
{
  float a = fBm (x, y, octaves);
  float b = ridgedmultifractal (x, y, octaves, 1, 8);
  float fade = fBm (x + 10.3, y + 10.3, octaves);

  const float width = 0.05f;

  if (fade > 0.5f + width)
    return a;
  else if (fade < 0.5f - width)
    return b;

  fade = (fade - 0.5f + width) / (width * 2);

  // sigmoidal curve
  fade = fade * fade * 2 * (1.5f - fade);

  return a * fade + b * (1 - fade);
}

float
frac_gen::ridgedmultifractal (float x, float y, int octaves, float offset, float gain)
{
  float sig = offset - fabsf (noise (x, y));
  sig *= sig;
  float v = sig;

  for (int i = 1; i < octaves; ++i)
    {
      rot [i](x, y);

      x *= lac;
      y *= lac;

      float w = clamp (sig * gain, 0.f, 1.f);

      sig = offset - fabsf (noise (x, y));
      sig *= sig;
      sig *= w;

      v += sig * ex [i];
    }

  return clamp (v * 0.25f, 0.f, .9999999f);
}

#if 1
void hack()
{
  frac_gen gen (0.5, 2);
  noise3d n(0);

#if 1
  int N = 1024;

  printf ("P5 %d %d 255\n", N, N);
  // pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm
  for (int y = 0; y < N; ++y)
    {
      if (!(y&63))fprintf (stderr, "y %d\n", y);//D
    for (int x = 0; x < N; ++x)
      {
        putc (127 * gen.noise (x * 0.04, y * 0.04) + 128, stdout);
        //putc (256 * gen.terrain2 (x * 0.004, y * 0.004, 8), stdout);
        //putc (256 * gen.fBm (x * 0.01, y * 0.01, 7), stdout);
        //putc (256 * gen.turbulence (x * 0.004 - 1, y * 0.004 - 1, 8), stdout);
        //putc (256 * gen.heterofractal (x * 0.008, y * 0.008, 8, -1.1, 2.0), stdout);
        //putc (256 * gen.ridgedmultifractal (x * 0.001, y * 0.001, 32, 1.001, 32), stdout);
      }
    }
#else
  int N = 128;

  //printf ("P6 %d %d 255\n", N, N);
  // pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm
  for (int z = 0; z < N; ++z)
    {
      if (!(z&4))fprintf (stderr, "z %d\n", z);//D
  for (int y = 0; y < N; ++y)
    for (int x = 0; x < N; ++x)
      {
        float v = n.noise (x * 0.06 + 0.2, y * 0.06 + 0.2, z * 0.06 + 0.2) * 0.5 + 0.5;

        if (z < 64)
          v = v * (z * z) / (64 * 64);

        if (v <= 0.1)
          continue;

        float r[4];
        int i[4];

        r[0] = x;
        r[1] = y;
        r[2] = z;
        r[3] = v;

        memcpy (i, r, 16);

        i[0] = htonl (i[0]);
        i[1] = htonl (i[1]);
        i[2] = htonl (i[2]);
        i[3] = htonl (i[3]);

        fwrite (i, 4*4, 1, stdout);
      }
    }
#endif

  exit (0);
}
#endif
Revision:	1.3
Committed:	Fri Apr 22 07:56:46 2011 UTC (13 years, 1 month ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+23 -18 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2			* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3			*
4			* Copyright (©) 2010 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5			*
6			* Deliantra is free software: you can redistribute it and/or modify it under
7			* the terms of the Affero GNU General Public License as published by the
8			* Free Software Foundation, either version 3 of the License, or (at your
9			* option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the Affero GNU General Public License
17			* and the GNU General Public License along with this program. If not, see
18			* <http://www.gnu.org/licenses/>.
19			*
20			* The authors can be reached via e-mail to <support@deliantra.net>
21			*/
22
23			#include "noise.h"
24
25	root	1.2	/////////////////////////////////////////////////////////////////////////////
26
27			noise2d::noise2d (uint32_t seed)
28	root	1.1	{
29			seedable_rand_gen rng (seed);
30
31			for (int i = 0; i < 256; ++i)
32			{
33	root	1.3	vec2d rv;
34			rv[0] = rng () - 0.5f;
35			rv[1] = rng () - 0.5f;
36	root	1.1
37			// normalise
38	root	1.3	float mag = 1.f / sqrtf (rv[0] * rv[0] + rv[1] * rv[1]);
39
40			rv[0] *= mag;
41			rv[1] *= mag;
42	root	1.1
43	root	1.3	rvec[i][0] = rv[0];
44			rvec[i][1] = rv[1];
45	root	1.1	}
46
47	root	1.3	rvmap[0].seed (rng);
48			rvmap[1].seed (rng);
49	root	1.1	}
50
51			float
52	root	1.2	noise2d::noise (float x, float y)
53	root	1.1	{
54			int ix = floorf (x); float fx = x - ix;
55			int iy = floorf (y); float fy = y - iy;
56
57			float v = 0;
58
59			for (int j = -1; j <= 2; ++j)
60			for (int i = -1; i <= 2; ++i)
61			{
62			float Ax = fx - i;
63			float Ay = fy - j;
64
65	root	1.2	float d = Ax * Ax + Ay * Ay;
66	root	1.1
67			if (d < 4)
68			{
69			float t1 = 1 - d / 4;
70			float t2 = t1 * t1;
71			float t4 = t2 * t2;
72
73			float p = (4 * t1 - 3) * t4;
74	root	1.3
75			int h = rvmap[0](ix + i) ^ rvmap[1](iy + j);
76			float G0 = rvec[h & 0xff][0];
77			float G1 = rvec[h & 0xff][1];
78			//vec2d G = rvec[h & 0xff];
79
80			v += (Ax * G0 + Ay * G1) * p;
81	root	1.1	}
82			}
83
84			return clamp (v * 2, -.9999999f, .9999999f);
85			}
86
87	root	1.2	#if 0\|\|ABSTRACTION_PENALTY_IS_GONE
88			float
89			noise2d::noise (float x, float y)
90			{
91			vec2d X = vec2d (x, y);
92			gen_vec<2,int> I = floor (X);
93			vec2d F = X - I;
94
95			float v = 0;
96
97			for (int j = -1; j <= 2; ++j)
98			for (int i = -1; i <= 2; ++i)
99			{
100			vec2d A = F - vec2d (i, j);
101
102			float d = A * A;
103
104			if (d < 4)
105			{
106			int h = rvmap [0](I[0] + i) ^ rvmap [1](I[1] + j);
107			float *G = rvec [h & 0xff];
108
109			float t1 = 1 - d / 4;
110			float t2 = t1 * t1;
111			float t4 = t2 * t2;
112
113			float p = (4 * t1 - 3) * t4;
114			v += A * vec2d (G[0], G[1]) * p;
115			}
116			}
117
118			return clamp (v * 2, -.9999999f, .9999999f);
119			}
120			#endif
121
122			/////////////////////////////////////////////////////////////////////////////
123
124			noise3d::noise3d (uint32_t seed)
125			{
126			seedable_rand_gen rng (seed);
127
128			for (int i = 0; i < 256; ++i)
129			{
130			for (int j = 0; j < 3; ++j)
131			rvec [i][j] = rng () - 0.5f;
132
133			// normalise
134			float mag = 1.f / sqrtf (rvec [i][0] * rvec [i][0]
135			+ rvec [i][1] * rvec [i][1]
136			+ rvec [i][2] * rvec [i][2]);
137
138			rvec [i][0] *= mag;
139			rvec [i][1] *= mag;
140			rvec [i][2] *= mag;
141			}
142
143			rvmap [0].seed (rng);
144			rvmap [1].seed (rng);
145			rvmap [2].seed (rng);
146			}
147
148			float
149			noise3d::noise (float x, float y, float z)
150			{
151			int ix = floorf (x); float fx = x - ix;
152			int iy = floorf (y); float fy = y - iy;
153			int iz = floorf (z); float fz = z - iz;
154
155			float v = 0;
156
157			for (int j = -1; j <= 2; ++j)
158			for (int i = -1; i <= 2; ++i)
159			for (int k = -1; k <= 2; ++k)
160			{
161			float Ax = fx - i;
162			float Ay = fy - j;
163			float Az = fz - k;
164
165			float d = Ax * Ax + Ay * Ay + Az * Az;
166
167			if (d < 4)
168			{
169			int h = rvmap [0](ix + i) ^ rvmap [1](iy + j) ^ rvmap [2](iz + k);
170			float *G = rvec [h & 0xff];
171
172			float t1 = 1 - d / 4;
173			float t2 = t1 * t1;
174			float t4 = t2 * t2;
175
176			// (4t⁵ - 3t⁴)
177			float p = (4 * t1 - 3) * t4;
178			v += (Ax * G[0] + Ay * G[1] + Az * G[2]) * p;
179			}
180			}
181
182			return clamp (v * 2, -.9999999f, .9999999f);
183			}
184
185			float
186			noise3d::noise (float x, float y, float z, float nx, float ny, float nz)
187			{
188			int ix = floorf (x); float fx = x - ix;
189			int iy = floorf (y); float fy = y - iy;
190			int iz = floorf (z); float fz = z - iz;
191
192			float v = 0;
193
194			for (int j = -1; j <= 2; ++j)
195			for (int i = -1; i <= 2; ++i)
196			for (int k = -1; k <= 2; ++k)
197			{
198			float Dx = fx - i;
199			float Dy = fy - j;
200			float Dz = fz - k;
201
202			float e = Dx * nx + Dy * ny + Dz * nz;
203
204			float o = 1 - abs (e);
205
206			if (o > 0)
207			{
208			float Ax = Dx - e * nx;
209			float Ay = Dy - e * ny;
210			float Az = Dz - e * nz;
211
212			float d = Ax * Ax + Ay * Ay + Az * Az;
213
214			if (d < 4)
215			{
216			int h = rvmap [0](ix + i) ^ rvmap [1](iy + j) ^ rvmap [2](iz + k);
217			float *G = rvec [h & 0xff];
218
219			float t1 = 1 - d / 4;
220			float t2 = t1 * t1;
221			float t4 = t2 * t2;
222
223			float o2 = o * o;
224
225			// (4t⁵ - 3t⁴) * (3o³ - 2o²)
226			float p = (4 * t1 - 3) * t4 * (3 * o2 - 2 * o2 * o);
227			v += (Ax * G[0] + Ay * G[1] + Az * G[2]) * p;
228			}
229			}
230			}
231
232			return clamp (v * 2, -.9999999f, .9999999f);
233			}
234
235	root	1.1	frac_gen::frac_gen (float hurst_expo, float lacunarity)
236	root	1.2	: h (hurst_expo), lac (lacunarity), noise2d (0)
237	root	1.1	{
238			float exsum = 0;
239
240			for (int i = 0; i < MAX_OCTAVES; ++i)
241			{
242			ex [i] = powf (lac, -h * i);
243			exsum += ex [i];
244			fbm_mul [i] = 0.5f / (exsum * 0.75f); // .75f is a heuristic
245			rot [i].set (0.4488f * i);
246			}
247			}
248
249			float
250			frac_gen::fBm (float x, float y, int octaves)
251			{
252			float v = 0.f;
253
254			for (int i = 0; i < octaves; ++i)
255			{
256			rot [i](x, y);
257
258			v += noise (x + i, y) * ex [i];
259
260			x *= lac;
261			y *= lac;
262			}
263
264			return clamp (v * fbm_mul [octaves - 1] + 0.5f, 0.f, .9999999f);
265			}
266
267			float
268			frac_gen::turbulence (float x, float y, int octaves)
269			{
270			float v = 0.f;
271
272			for (int i = 0; i < octaves; ++i)
273			{
274			rot [i](x, y);
275
276			v += fabsf (noise (x + i, y)) * ex [i];
277
278			x *= lac;
279			y *= lac;
280			}
281
282			return clamp (v * fbm_mul [octaves - 1] * 2.f, 0.f, .9999999f);
283			}
284
285			float
286			frac_gen::multifractal (float x, float y, int octaves, float offset)
287			{
288			float v = 1.f;
289
290			for (int i = 0; i < octaves; ++i)
291			{
292			rot [i](x, y);
293
294			v = noise (x, y) ex [i] + offset;
295
296			x *= lac;
297			y *= lac;
298			}
299
300			return clamp (v * 0.5f, 0.f, .9999999f);
301			}
302
303			float
304			frac_gen::heterofractal (float x, float y, int octaves, float offset)
305			{
306			float v = noise (x, y) + offset;
307			int i;
308
309			for (i = 1; i < octaves; ++i)
310			{
311			rot [i](x, y);
312
313			x *= lac;
314			y *= lac;
315
316			v += v * (noise (x, y) * ex [i] + offset);
317			}
318
319			return v / powf (2., octaves);
320			}
321
322			float
323			frac_gen::hybridfractal (float x, float y, int octaves, float offset, float gain)
324			{
325			float v = (noise (x, y) + offset) * ex [0];
326			float weight = v;
327			int i;
328
329			for (i = 1; i < octaves; ++i)
330			{
331			rot [i](x, y);
332
333			x *= lac;
334			y *= lac;
335
336			min_it (weight, 1.f);
337
338			float sig = (noise (x, y) + offset) * ex [i];
339			v += weight * sig;
340			weight = gain sig;
341			}
342
343			return clamp (v * 0.5f + 0.5f, 0.f, .9999999f);
344			}
345
346			// http://www.gamasutra.com/view/feature/3098/a_realtime_procedural_universe_.php?page=2
347			float
348			frac_gen::terrain (float x, float y, int octaves)
349			{
350			float v = 0.f;
351
352			for (int i = 0; i < octaves; ++i)
353			{
354			rot[i] (x, y);
355
356			v += noise (x + i, y) * ex [i];
357
358			x *= lac;
359			y *= lac;
360			}
361
362			v *= fbm_mul [octaves - 1];
363
364			return v <= 0.f ? - powf (-v, 0.7f) : powf (v, 1. + noise (x, y) * v);
365			}
366
367			float
368			frac_gen::terrain2 (float x, float y, int octaves)
369			{
370			float a = fBm (x, y, octaves);
371			float b = ridgedmultifractal (x, y, octaves, 1, 8);
372			float fade = fBm (x + 10.3, y + 10.3, octaves);
373
374			const float width = 0.05f;
375
376			if (fade > 0.5f + width)
377			return a;
378			else if (fade < 0.5f - width)
379			return b;
380
381			fade = (fade - 0.5f + width) / (width * 2);
382
383			// sigmoidal curve
384			fade = fade * fade * 2 * (1.5f - fade);
385
386			return a * fade + b * (1 - fade);
387			}
388
389			float
390			frac_gen::ridgedmultifractal (float x, float y, int octaves, float offset, float gain)
391			{
392			float sig = offset - fabsf (noise (x, y));
393			sig *= sig;
394			float v = sig;
395
396			for (int i = 1; i < octaves; ++i)
397			{
398			rot [i](x, y);
399
400			x *= lac;
401			y *= lac;
402
403			float w = clamp (sig * gain, 0.f, 1.f);
404
405			sig = offset - fabsf (noise (x, y));
406			sig *= sig;
407			sig *= w;
408
409			v += sig * ex [i];
410			}
411
412			return clamp (v * 0.25f, 0.f, .9999999f);
413			}
414
415	root	1.3	#if 1
416	root	1.1	void hack()
417			{
418			frac_gen gen (0.5, 2);
419	root	1.2	noise3d n(0);
420	root	1.1
421	root	1.3	#if 1
422	root	1.1	int N = 1024;
423
424	root	1.3	printf ("P5 %d %d 255\n", N, N);
425	root	1.1	// pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm
426			for (int y = 0; y < N; ++y)
427			{
428			if (!(y&63))fprintf (stderr, "y %d\n", y);//D
429			for (int x = 0; x < N; ++x)
430			{
431	root	1.3	putc (127 * gen.noise (x * 0.04, y * 0.04) + 128, stdout);
432	root	1.2	//putc (256 * gen.terrain2 (x * 0.004, y * 0.004, 8), stdout);
433	root	1.3	//putc (256 * gen.fBm (x * 0.01, y * 0.01, 7), stdout);
434	root	1.1	//putc (256 * gen.turbulence (x * 0.004 - 1, y * 0.004 - 1, 8), stdout);
435			//putc (256 * gen.heterofractal (x * 0.008, y * 0.008, 8, -1.1, 2.0), stdout);
436			//putc (256 * gen.ridgedmultifractal (x * 0.001, y * 0.001, 32, 1.001, 32), stdout);
437			}
438			}
439	root	1.2	#else
440			int N = 128;
441
442			//printf ("P6 %d %d 255\n", N, N);
443			// pmake&&server/deliantra-server >x&&convert -depth 8 -size 512xx512 gray:x x.ppm&& cv x.ppm
444			for (int z = 0; z < N; ++z)
445			{
446			if (!(z&4))fprintf (stderr, "z %d\n", z);//D
447			for (int y = 0; y < N; ++y)
448			for (int x = 0; x < N; ++x)
449			{
450			float v = n.noise (x * 0.06 + 0.2, y * 0.06 + 0.2, z * 0.06 + 0.2) * 0.5 + 0.5;
451
452			if (z < 64)
453			v = v * (z * z) / (64 * 64);
454
455			if (v <= 0.1)
456			continue;
457
458			float r[4];
459			int i[4];
460
461			r[0] = x;
462			r[1] = y;
463			r[2] = z;
464			r[3] = v;
465
466			memcpy (i, r, 16);
467
468			i[0] = htonl (i[0]);
469			i[1] = htonl (i[1]);
470			i[2] = htonl (i[2]);
471			i[3] = htonl (i[3]);
472
473			fwrite (i, 4*4, 1, stdout);
474			}
475			}
476			#endif
477	root	1.1
478			exit (0);
479			}
480			#endif